It is the object of the present invention a new type of hinge, particularly for the hinging of temples on the front of spectacles, which allows the automatic closing, free or adjustable, of the temples on the same front of spectacle which is removed from the head or which however features one or both temples in open or wide-open position.
The main feature of the present invention is to provide for a hinging element, generally the stationary unit attached to the endpiece head or side end of the front, which is cam-shaped with a particular profile, on which a guided follower runs, with the possibility of interposing a dynamic compensation device, into a hole made on the head of the other part or element to be hinged, being this follower driven by an elastic medium which acts axially to the hinge pin and being the cam profile provided with a progressive shape which is always disposed on a plane inclined with respect to the thrust axis of the roller follower.
The very large majority of the devices for increasing the elasticity of the spectacle temples is obtained with the two side ends of the front endowed with a hinge head which is cam-shaped, having two sides orthogonal to each other and equidistant from the hinge hole, after previous adequate rounding off their convergence angle.
As it is known, though in the several construction forms known at present, the temple end to be attached is hinged to this square head, after that a follower has been inserted in the axial head hole of the cam, which follower is pushed against the sides of the same square head, by an elastic medium, so achieving the aim of a moderate and controlled pressure of the temples on the head, for an easier use of the spectacles, in addition to the possibility of having a closing or opening release, when passing from one to the other side of the square head.
This system for improving the elasticity of the spectacle temples has undoubtedly made wearing spectacles easier, without having to push continually the spectacles back up the nose to place them in the correct optical position, since conventional temples did not ensure the positioning on the head.
Yet, it is not infrequent the case of spectacle temples which, however releasing from an open to a closed position and vice versa, do not ensure the stability of the open position, since, for wear of the cam or for stress relaxation of the elastic medium, its follower does not rest anymore on one of the sides of the square head of the front end, causing a certain backlash or oscillation of the same temple.
Moreover, it is known that the abrupt release with which the temple opens or closes on the endpiece, causes an annoying feeling of being not able to control its motion. In particular, when closing the temples on the front, this sudden release may also constitute a serious danger because of the contact of the temples with the eyes.
Primary object of the present invention is that of accomplishing a spectacle whose temples can close automatically, gradually, and without sudden releases.
Another object of the present invention is that of removing any possible backlash or idle oscillation of the temple, particularly following wear by contact with the fixed part of the hinge.